Rays acquire reliever Dan Jennings from White Sox for minor leaguer

— -- The Tampa Bay Rays strengthened their bullpen for the stretch run Thursday, acquiring left-handed reliever Dan Jennings from the Chicago White Sox in a trade for first-base prospect Casey Gillaspie.

Jennings, 30, is 3-1 with a 3.45 ERA this season. His 48 appearances lead American League lefties and are tied for second among all AL relievers behind Cleveland's Bryan Shaw.

Jennings tweeted goodbye to Chicago on Thursday.

Jennings has limited lefty hitters to a .169 average and one extra-base hit in 71 at-bats this year. His 58.5 percent ground-ball rate ranks sixth in the American League.

Gillaspie, 24, logged a .227/.296/.357 slash line (batting average/on-base percentage/slugging percentage) with nine home runs in 95 games for Tampa's Triple-A Durham farm club. Last year, he led Rays minor leaguers with 18 home runs.

Gillaspie was Tampa's first-round pick and the 20th selection overall in the 2014 MLB first-year player draft. He is the younger brother of San Francisco Giants infielder Conor Gillaspie.